The free edition of XenServer starts with a 64-bit hypervisor and centralized management, live migration, and conversion tools to create a virtual platform that maximizes guest density and performance.

I currently no longer use this at home (not because I don’t like it, rather I have slimmed down my home server environment).

Quick Look: Citrix XENServer 5.6 SP2

The premium editions of XenServer extend the platform to enable organizations of any size to integrate and automate management processes, delivering a virtual datacenter solution.